A high proportion of human embryos obtained through IVF from women 35 and older are aneuploid, in part explaining the decrease in implantation with maternal age. This project will develop an efficient and safe method to screen oocytes for all aneuploidies. Its clinical application should result in an increase in pregnancy rates after IVF and a reduction in aneuploid conceptions. Polar bodies, non-essential for embryo development, will be biopsied from each oocyte and analyzed by multicolor FISH. Research material will be polar bodies from unfertilized or in-vitro matured M-I oocytes. Because chromatin degenerates rapidly in polar bodies, a biopsy method will be developed to provide reliable cytogenetic information with low risk of damaging oocytes or zygotes. Different temperature and humidity conditions as well as fixative solutions will be assessed to optimize polar body fixation. Initially, only those chromosomes most responsible for oocyte aneuploidy will be assessed. These will be determined by studying a sizable number of oocytes. In a phase Il SBIR proposal, all chromosomes will be assessed by using combinations of 5 or more fluorochromes and resolution through image analysis. PROPOSED COMMERCIAL APPLICATIONS Preimplantation diagnosis for all aneuploidies in polar bodies would be developed to improve IVF outcome by reducing the chances of conceiving a baby with trisomy, and increasing pregnancy rates. Most IVF units cannot perform this procedure, so The ART Institute of NY & NJ could receive fixed polar bodies from these units for diagnosis before embryo transfer at those IVF centers.